The present disclosure relates generally to semiconductor manufacturing. Specifically, the present disclosure relates to devices with bulk silicon moving members that have dimples and methods of making the same.
The semiconductor integrated circuit (IC) industry has experienced rapid growth. Technological advances in IC materials and design have produced generations of ICs where each generation has smaller and more complex circuits than the previous generation. However, these advances have increased the complexity of processing and manufacturing ICs and, for these advances to be realized, similar developments in IC processing and manufacturing are needed. In the course of IC evolution, functional density (i.e., the number of interconnected devices per chip area) has generally increased while geometry size (i.e., the smallest component that can be created using a fabrication process) has decreased.
Micro-electro-mechanical systems (MEMS) devices include very small electro-mechanical systems incorporated into semiconductor IC circuits. Some MEMS devices have moving members separated from the substrate by a gap and one or more bumps. The bumps are on top of the substrate and may be in contact with a sensing electrode. As a moving member moves toward the substrate, its movement is constrained by the bumps, and a sensing electrode senses the movement. When some materials, such as oxides, are used for bumps the resulting device may experience parasitic capacitance and stiction at the interface between the bumps and the moving member. Parasitic capacitance and stiction may make the resultant device ineffective in sensing some movement.
Similarly, using metal for bumps may require an additional metal routing step, thereby making the resultant device incrementally more expensive to manufacture. Therefore, what is needed is an improved MEMS device and method for making the same.